Victron combi versus Separates

[starman]

1 hour ago, WotEver said:

 

I don’t know why so many boaters assume things about the BSS instead of simply reading the regs for themselves. THEN if something is unclear by all means ask for clarification. 

https://www.boatsafetyscheme.org/media/268789/ecp-private-boats-ed3_rev2_apr2015_public_final.pdf

You're quite right - slapped wrists duly suffered ;-)

[Sea Dog]

4 hours ago, Dr Bob said:

Thanks for that Sea Dog. That does look interesting and a good price compared to the Sterling. I looked at the specs and it seems the max Absorption voltage is 14.6V and I couldnt see anything about temperature compensation so can it push out 14.8V when the batteries are cold (5°C)?

Looking at this victron one, and the Sterling one, - and all the other really useful stuff in this thread, it has lead me to a question that I need to get an answer to before making any more progress. "How are you all monitoring tail current to ensure you are 100% SOC"?

With my Victron combi, I never get a stable tail current as the unit switches out of Absorption while the current is still decreasing ie it goes to float (so the voltage goes sub 14.0V) with the Amps at 10-12A (660Ahr bank). As in a previous post, I think the combi is likely set to Predictive charging rather than Fixed charging - but I will check tomorrow when I get the front off. If I set it to Fixed, then it will stay in Absorption for the time I set it as - so say 1hr. This will enable me to watch the tail current and if it is still dropping after 1hr, I can switch the combi off and on again to give it another hour. The snag here is the TV/Pie/BT TV box/router goes off plus if I do need 3 to 4 hours charge as the batteries are low then I will have to be on the boat to keep reseting. What I think I need is a charger that I can switch easily from a method of charging a battery at say 60% of charge - where it needs to be on absorption for a reasonable time and it can go to float when it sees fit, to one where I can keep it in absorption for enough time to watch the tail current. The Combi box I have doesnt allow that without taking the cover off and faffing with dip switches. I guess I could put it into Fixed charging and give it a time of 3hrs but will that then wreck the batteries by overcharging when I plug in with the batteries full?

I am drawn towards the Sterling charger as I can change programme via easily accessible dip switches but can I specify either a 'time' based or 'adaptive' based switching or does the Sterling always make up its mind when to go to float based on its own view of tail current? How have you all got your chargers set up to see the tail current?

The Victron manual has a bit more detail than their spec sheet. Key points from your concerns above:

It does do temperature compensation. The rate applied is 16mv per degree C. Absorption voltage in high at ambient temperature is 14.7V.

It automatically varies the Absorption timings from 30 mins if the battery is almost full at switch on up to 8 hours for a heavily discharged battery.

The maximum output voltage it can achieve appears to be 16.5V in 'high' recondition mode.

Hope that helps.

 

[Robbo]

Re-reading the manual in adaptive charging mode the default max absorption time is 4 hours, this may be too low for your batteries.  It can be changed to 8hrs max (page 12)

[WotEver]

3 minutes ago, Robbo said:

Re-reading the manual in adaptive charging mode the default max absorption time is 4 hours, this may be too low for your batteries.  It can be changed to 8hrs max (page 12)

And if it’s on ‘timed’ as opposed to ‘current detected’ or whatever Victron calls it then I guess it can simply be restarted. 

[Robbo]

4 minutes ago, WotEver said:

And if it’s on ‘timed’ as opposed to ‘current detected’ or whatever Victron calls it then I guess it can simply be restarted. 

 Well even on adaptive charging if the max time is reached it will flip into float.   Does this sound fisable for what you are seeing @Dr Bob?

Edited December 17, 2017 by Robbo

[WotEver]

2 minutes ago, Robbo said:

 Well even on adaptive charging if the max time is reached it will flip into float.   Does this sound fisable for what you are seeing @Dr Bob?

Yeah, but if I understand the options, you have “Switch to float when current = x or after y hours, whichever comes first” or you have “Switch to float after y hours”. The latter might be more useful as you can keep restarting it until the tail current is low at Absorption voltage. 

[Robbo]

7 minutes ago, WotEver said:

Yeah, but if I understand the options, you have “Switch to float when current = x or after y hours, whichever comes first” or you have “Switch to float after y hours”. The latter might be more useful as you can keep restarting it until the tail current is low at Absorption voltage. 

just re-read ya reply, yes if y hours is not set high enough then it will flip into float in the adaptive charging mode.

 

Adaptive Charging Characteristic:
The absorption period depends on the charge delivered during bulk. This is followed by float phase lasting 24 hours, after which the voltage is reduced by an additional 0,8 V resp. 1,6 V for 12 V resp. 24 V batteries. (reduced float). As with the Fixed-charging characteristic, the charger will periodically switch back to absorption.

 

Edited December 17, 2017 by Robbo

[Dr Bob]

36 minutes ago, WotEver said:

Yeah, but if I understand the options, you have “Switch to float when current = x or after y hours, whichever comes first” or you have “Switch to float after y hours”. The latter might be more useful as you can keep restarting it until the tail current is low at Absorption voltage. 

Yes. Thanks to you and Robby for getting there. I don't think there is any way to change the current =x so better to use hours as the switch. If I set it to 3 hrs, am I going to knacker the batteries if they are full, the shore power goes off and then on thus starting a new absorption 3 hr cycle at 12.8v? I guess it will be fine as the current will reduce to the tail current.

2 hours ago, Sea Dog said:

The Victron manual has a bit more detail than their spec sheet. Key points from your concerns above:

It does do temperature compensation. The rate applied is 16mv per degree C. Absorption voltage in high at ambient temperature is 14.7V.

It automatically varies the Absorption timings from 30 mins if the battery is almost full at switch on up to 8 hours for a heavily discharged battery.

The maximum output voltage it can achieve appears to be 16.5V in 'high' recondition mode.

Hope that helps.

 

Thanks Sea dog, I will have a close look at the manual.

[WotEver]

2 hours ago, Dr Bob said:

If I set it to 3 hrs, am I going to knacker the batteries if they are full, the shore power goes off and then on thus starting a new absorption 3 hr cycle at 12.8v? I guess it will be fine as the current will reduce to the tail current.

No

[Dr Bob]

On 16/12/2017 at 20:17, Sea Dog said:

A while since you asked thid, but someone else brought it to the surface.  If 30a would do you, and I share your reasoning, take a look at the latest Victron IP22 Blue Power or Blue Smart chargers. I quite like the look of matching gear, but there's better reasons than that - they're relatively inexpensive, compact, quite smart and highly configurable and also have a Lithium Ion setting so future ready.

I've just fitted the 30a Blue Smart to my 400+ domestic bank. If ever 30a is insufficient my alternator does 175a. 

Sea Dog. I have looked at the manual and indeed it does look very good for the price. A question. When the batteries are almost full (or full) and you put it on, does it stay in Absorption for the minimum 30 mins each time. That would then be good enough to monitor tail current. Otherwise it seems to tick all the boxes. Not quite as configurable as the Sterling Pro charge but the limited Voltage settings seem to cover everything I need. Its much smaller than the Sterling an a lot cheaper.

[Sea Dog]

2 hours ago, Dr Bob said:

Sea Dog. I have looked at the manual and indeed it does look very good for the price. A question. When the batteries are almost full (or full) and you put it on, does it stay in Absorption for the minimum 30 mins each time. That would then be good enough to monitor tail current. Otherwise it seems to tick all the boxes. Not quite as configurable as the Sterling Pro charge but the limited Voltage settings seem to cover everything I need. Its much smaller than the Sterling an a lot cheaper.

I've not sat and timed it, but it certainly stays in absorption mode for a while after a restart. I have no reason to think it's not doing exactly what it says it does and giving a 30 minutes minimum in that mode when it senses fully charged batteries. I also particularly like that it can operate as a 12V power supply, how compact it is for its maximum current rating, and that it has an automatically self cancelling night mode where it will run silently (at half max output) for 8 hours overnight. In practice, I've never actually heard the fan as even in the bulk phase I've not had it charging at high enough current to make the cooling fan cut in, so it's totally silent all the time whereas my Mastervolt Combi fan ran constantly in charger mode. Quality wise, I think most would put Victron above Sterling.

I've only had mine in service for a couple of weeks, having been through the same sort of research route you're on now. So far, however, it's met all of my needs and most of my expectations. Mine's the Bluetooth version (BlueSmart), and I can't say the higher detail of what it's doing is essential, but the first thing mine did was update the charger's firmware (from v2.xx to v3.00) from the Web via the smartphone app. Handy to be able to do that if/when Victron make program improvements. The Bluetooth range is limited though, so I can't sit in my saloon at the bow end and connect to the charger at the stern. In practice, long range is not really essential and as long as you are in half a boat length the app does let you see what your charger is doing in more detail - which sounds right up your street! If you download the app, there's a basic demo mode for compatible Victron devices.

[Dr Bob]

1 hour ago, Sea Dog said:

 

I've only had mine in service for a couple of weeks, having been through the same sort of research route you're on now. So far, however, it's met all of my needs and most of my expectations. Mine's the Bluetooth version (BlueSmart), and I can't say the higher detail of what it's doing is essential, but the first thing mine did was update the charger's firmware (from v2.xx to v3.00) from the Web via the smartphone app. Handy to be able to do that if/when Victron make program improvements. The Bluetooth range is limited though, so I can't sit in my saloon at the bow end and connect to the charger at the stern. In practice, long range is not really essential and as long as you are in half a boat length the app does let you see what your charger is doing in more detail - which sounds right up your street! If you download the app, there's a basic demo mode for compatible Victron devices.

I'm glad you posted that. I hadnt realised there was a 'Bluesmart' version. That sounds like a really good idea. I will have a look at the app. At less than £200, it looks a good buy. The only thing putting me off is that it is only 30A. Our domestic bank is 660Ahr but the only time we normally go on shore power is on returning from a trip to the marina and so the engine has been charging therefore never likely to be less  than say 60-70% charged if that and most likely >90%. I assume the unit can deliver 30A for a number of hours so worst case 30A for say 8 hours?

I am thinking about the 3 socket approach - earlier in the thread - so it wouldnt be difficult to wire it so my existing combi, to be used as the inverter, could have a wire from the AC input to a plug that could go to the shore power boat socket and hence the combo could go back to being a combo and not just an inverter. I therefore get all my options with separates, a controllable battery charger and shore power that is not messed up with combi if it goes wrong, but being able to go back to the original layout by just changing the plugs round.

A final question to all is about equalisation charge current. This 30A charger does its equalisation at 8% of its normal current so 2.4A. Is that current high enough for the 660Ahr? If not I can easily isolate half the bank and do half at a time.

[Sea Dog]

28 minutes ago, Dr Bob said:

I'm glad you posted that. I hadnt realised there was a 'Bluesmart' version. That sounds like a really good idea. I will have a look at the app. At less than £200, it looks a good buy.

I paid £178.50 at Battery Megastore on eBay with no issues.

The only thing putting me off is that it is only 30A. Our domestic bank is 660Ahr but the only time we normally go on shore power is on returning from a trip to the marina and so the engine has been charging therefore never likely to be less  than say 60-70% charged if that and most likely >90%. I assume the unit can deliver 30A for a number of hours so worst case 30A for say 8 hours?

Victron say: "Bulk charges the battery with maximum current until absorption voltage is reached. The battery will then be about 80%  charged and is ready for use". If you do end up mooring  with very low battery charge (unlikely, I'd agree), it'll just take longer. Personally, I'd let the alternator take the strain til charge current was down to 30a and then let the charger take over. Getting to 30a when cruising rarely takes very long in my experience.

I am thinking about the 3 socket approach - earlier in the thread - so it wouldnt be difficult to wire it so my existing combi, to be used as the inverter, could have a wire from the AC input to a plug that could go to the shore power boat socket and hence the combo could go back to being a combo and not just an inverter. I therefore get all my options with separates, a controllable battery charger and shore power that is not messed up with combi if it goes wrong, but being able to go back to the original layout by just changing the plugs round.

It can work perfectly well I have no doubt and may be a good interim fix to get the last miles out of an ailing Combi with a duff charger (like I have!) but, even done well, this method will have the look and smell of a bodge to me!  If/when you come to sell the boat, is a prospective buyer gonna be impressed by your ingenuity or would you end up replacing the semi-duff Combi to satisfy a prospective buyer or his surveyor? Incidentally, should you ever need a separate replacement, a new Victron Phoenix 12/2000 Inverter (to match your existing inverter's capacity) can be had for £636 inc vat and delivery from www.powersavingsolutions.co.uk, about £200 quid under the best usual suspects' prices. Plus, their customer service is awesome. 

A final question to all is about equalisation charge current. This 30A charger does its equalisation at 8% of its normal current so 2.4A. Is that current high enough for the 660Ahr? If not I can easily isolate half the bank and do half at a time.

I believe Victron have gone to some trouble to ensure a very low current at the higher voltage involved, but others may be able to give you a more definitive view.  I see no reason to preclude desulphating half a bank at a time, other than the faff (neither the charger not the batteries will know ;))  but whether there's an advantage depends on the expert answer to your equalisation current question. Are your batteries of a type compatible with regular equalisation?

 

 

 

[cuthound]

1 hour ago, Dr Bob said:

A final question to all is about equalisation charge current. This 30A charger does its equalisation at 8% of its normal current so 2.4A. Is that current high enough for the 660Ahr? If not I can easily isolate half the bank and do half at a time.

As equalisation should be undertaken on a fully charged battery, a a raised voltage (typically 15.0-16.0 volts for a 12 volt battery at 25°C - check manufacturers instructions), the current is likely to be just a little higher than the absortion charge tail current.

Edited December 18, 2017 by cuthound
Spillung

[Dr Bob]

On 18/12/2017 at 16:47, Sea Dog said:

I paid £178.50 at Battery Megastore on eBay with no issues

 

 

Sea Dog,

Did you get the one outlet version?

I am looking to be able to charge the engine start battery as well so will need to get the 3 outlet version. Anyone out there with the 3 outlet one? Not sure how it will control and if the two battery outlets can be controlled independently ie one on float and and one on absorption.

[Sea Dog]

8 hours ago, Dr Bob said:

Sea Dog,

Did you get the one outlet version?

I am looking to be able to charge the engine start battery as well so will need to get the 3 outlet version. Anyone out there with the 3 outlet one? Not sure how it will control and if the two battery outlets can be controlled independently ie one on float and and one on absorption.

I got the single outlet one. I tried hard to find out how having a full engine/thruster pair and a heavily discharged domestic bank (or vice versa) would be handled by the 3 outputs version when one needs float and the other needs bulk but got nowhere really.  So I went with the single for my domestics and fitted a Ctek Comfort Indicator to monitor the engine/thruster pair and I plug in a 5a Ctek smart charger should I need to. Now each battery bank gets what it needs. I'm sure the power sharing would have been ok, but I like to know what's going on.